This invention relates in general to medical diagnostic devices and methods in the field of human and animal health.
Considering the cost of blood tests and the invasive nature of exploratory blood sampling, physicians are increasingly reluctant to prescribe full assessments too frequently for their patients.
This results in an obvious under-detection of certain diseases the detection of which is made primarily by blood testing, such as diabetes, hypertension, hyperthyroidism, coronary diseases, . . . .
Furthermore, when these diseases are detected, it is often very difficult or costly to evaluate the effectiveness of the prescribed treatment, because, in actual practice, it is impossible to conduct daily bioanalyses.
In addition, various electrophysiological measurement systems are known, such as electrocardiography or electroencephalography apparatuses. These systems are passive in the sense that they measure electrical phenomena produced naturally by the human body, and have the advantage of being non-invasive, however the diagnostic possibilities of same are limited.
So-called active electrophysiological measurement systems are likewise known, which are based on impedance measurement. The operating principle of these apparatuses consists in running currents between various electrodes placed on the body, and in examining the way in which certain regions of the body attenuate this current. As a matter of fact, these rather high-frequency techniques have the disadvantage of depending heavily on the skin/electrode interface and, in particular, on the capacitive effect thereof. The reproducibility of measurements between patients, or even on one patient, is subject to reserve for these high-frequency measurements. As for very low-frequency measurements, they can be harmful to cells.
In addition, diagnostic systems are already known in which rectangular-wave voltages of a certain frequency are applied to electrodes placed on the fingers of a single hand, which frequency is necessarily high in order to be capable of detecting capacitive phenomena on the skin, and the current flowing in this portion of the body in response to this rectangular-wave voltage is studied. This system has evolved in order to incorporate a Fourier analysis in connection with the high frequency of the waves, which provides spectral distribution of the current observed. However, this known system has applications which are limited to very localized detections (in the area of the fingers of the hands and the feet), and enables diagnoses to be made only within the limits of conventional acupuncture techniques.
The applicant has already succeeded in broadening the diagnostic possibilities of electrophysiological-type systems by enabling same to detect a certain number of illnesses, diseases, pathological areas or other disorders normally detectable by testing blood or another bodily fluid.
The applicant has thus developed a simple-to-use, non-invasive diagnostic system having degrees of specificity and sensitivity which are equivalent to laboratory tests and which enables certain diseases, certain pathological predispositions or certain organ dysfunctions to be detected with improved reliability and with a broader range of possibilities.
This analysis system is described in the document FR-A-2 887 427.
This invention aims to propose an improved system, which, in particular, makes it possible to take account of the evolution of electrochemical phenomena occurring in the body based on the level of voltage to which the electrodes are subjected.
The invention likewise aims to propose a method of processing data with a view to developing a diagnosis, which is capable of taking account of measurements revealing such electrochemical phenomena.
To that end, according to a first aspect, an electrophysiological analysis system is proposed, which is intended, in particular for the detection of pathological conditions, characterised in that it includes:
a series of electrodes capable of being placed at various regions of the human body distant from one another,
an adjustable DC voltage source which, in response to the control circuit, is capable of producing successive waves of a DC voltage which varies from one wave to the other, the duration of the waves being greater than or equal to approximately 0.2 second,
a switching circuit capable of selectively connecting a pair of so-called active electrodes to the voltage source, and of connecting at least one other high-impedance electrode, and
a measuring circuit capable of collecting data representative of the current in the active electrodes and of the potentials on at least some electrodes connected in high impedance, in response to the application of said waves,
and in that, from one wave to the other, the range of voltages covered by the waves is capable of causing the appearance or disappearance of electrochemical phenomena in the vicinity of the active electrodes.
Certain preferred but non-limiting aspects of this system are as follows:                The system further includes a processing device capable of analyzing the reciprocal evolution of said current and said potentials in relation to the voltage of the waves, and of comparing such evolution to at least one reference evolution.        The switching circuit is capable of successively connecting various pairs of active electrodes to said voltage source.        When a pair of electrodes is connected to the voltage source, the switching circuit is capable of connecting all of the other high-impedance electrodes.        The measuring circuit includes a resistor capable of being connected between one of the electrodes of an active pair and a reference voltage.        The system likewise includes a calibration circuit which, for a given pair of active electrodes, is capable of adjusting the value of the measurement resistor so that it is of the same order of magnitude as the resistance present between the two active electrodes in the presence of a DC voltage.        The calibration circuit is capable of adjusting the value of the measurement resistor so that it is close the resistance of the human body.        The data representative of the current in the active electrodes derives from the potential difference measured at the terminals of the measurement resistor.        The measuring circuit is capable of measuring the potentials on all of the electrodes.        The voltage waves have a voltage value of between approximately 1 and 4 volts and a duration of between approximately 0.5 and 5 seconds.        The voltage of the successive waves varies in one direction and then in another.        The voltage of the successive waves varies by a first step, and then by a second step, which is smaller than the first.        The voltage of the successive waves varies in step between approximately 0.05 and 1 volt        The successive waves are spaced apart by a duration of between approximately 0.5 and 5 seconds.        The switching circuit is capable of connecting a single pair of electrodes to the voltage source in two reversed polarities.        The system includes two electrodes for left and right frontal lobes, two electrodes for left and right hands and two electrodes for left and right feet.        The switching circuit is capable of connecting, to the voltage source, electrode pairs consisting of the left forehead electrode and the right forehead electrode, the right forehead electrode and the left forehead electrode, the left hand electrode and the right hand electrode, the right hand electrode and the left hand electrode, the left foot electrode and the right foot electrode and the right foot electrode and the left foot electrode.        After having connected a certain pair of electrodes to the voltage source with a certain polarity, the switching circuit is capable of connecting this same pair of electrodes to the voltage source with a reversed polarity, only after another distant pair of electrodes on the body has been connected to the voltage source.        
According to a second aspect of the invention, a method is proposed for diagnosing a patient, with a view to detecting a disease, a pathological predisposition or another disorder, characterised in that it includes the following steps:                receiving a set of data comprising measurements revealing electrochemical phenomena in the vicinity of the electrodes applied to the skin of the patient at predetermined locations on the body,        accessing at least one set of stored reference data comprising measurements revealing electrochemical phenomena, which were obtained under the same conditions, on patients identified as suffering or not suffering from this disease, and        reconciling said set of data received with the sets of reference data, and, based on proximity criteria between the set of data received and the sets of reference data, identifying the patient as ill or not ill.        
Preferred but non-limiting aspects of this method are as follows:                The data sets further include data of a physiological and/or behavioural and/or environmental nature.        The data sets comprise measurements taken on a patient after a predetermined exertion by the patient.        The measured data is obtained from current values in the active electrodes and from potential values on high-impedance electrodes, in response to the application of voltage waves between active electrodes, the level of which varies from one wave to the other, in order to cause the appearance or disappearance of electrochemical phenomena in the vicinity of the active electrodes.        Said measurements are provided by a system as defined above.        The method is implemented in computer equipment which is remote from the system and connected thereto via a data communication channel.        